Why do pure solvents show a level of horizontal curve as solidification occurs, but the curve for the solution sloped downward slightly?
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A solution will freeze depending on the concentration of solute (colligative properties) As the solution freezes, the concentration changes, so the temperature of solidification will slope.
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yah answers
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The difference in the behavior of pure solvents and solutions during solidification is due to the presence of solute particles in the solution.
When pure solvents solidify, their temperature decreases gradually until they reach the freezing point, at which point solidification occurs. During this process, the solidification curve typically shows a slight horizontal plateau. This plateau occurs because the energy released during the phase transition is not enough to further decrease the temperature of the solvent. As a result, the temperature remains relatively constant until the entire solvent has solidified.
On the other hand, when a solute is dissolved in a solvent to form a solution, the presence of solute particles affects the solidification process. The solute particles disrupt the orderly arrangement of the solvent molecules, making it more difficult for the solvent to crystallize and solidify. As a result, the solidification curve for solutions does not show a horizontal plateau, but instead slopes downward slightly. This downward slope indicates that the solution's temperature continues to decrease as solidification occurs, unlike pure solvents where the temperature remains constant during solidification.
To understand and observe these phenomena, experimental measurements of temperature changes and phase transitions are required. By carefully monitoring the temperature changes during the solidification of pure solvents and solutions, scientists and researchers can analyze the curves obtained and gain insights into the behavior of these systems.